On Nov 25, 2016, at 21:14 , Carl Hoefs <
email@hidden> wrote:
You'd think by the time Xcode 8 rolled out that you'd be able to drag-n-drop in a single 512x512 PNG image and Xcode would rescale it to the various sizes needed.
In fact, you can drop in a single 512 x 512 image and it will be rescaled to the various sizes needed, just not by Xcode. That is, it’s perfectly acceptable to supply only the higher-resolution image, and let the target system scale it down to the smaller sizes as necessary. AFAIK, this has always been true, even in the classic Mac OS that preceded OS X.
The point of having image slots at smaller sizes is to allow you to customize the image for each size, in a “better” way than just by scaling. Sometimes you may want to tweak a pixel, other times you may want a different design for the smaller icons.
I would imagine that the need for customized low-res images is gradually going to go away, as retina-style displays become ubiquitous. If the display has sufficient resolution, the result of algorithmic scaling tends to become acceptable without customization.